“Short-range” radio communication is understood in the present description to mean radio distances (cell radii) of up to several kilometers
In their functions, role distributions and interfaces, modern road-toll systems follow the principles defined in ISO Standard 17573, “Road Transport and Traffic Telematics—Electronic Fee Collection—System Architecture for Vehicle Related Transport Services.” According to the latter there are essentially two basic types of systems.
“infrastructure-bound” systems, e.g., DSRC (dedicated short-range communication) toll systems, in which roadside infrastructure (roadside equipment, RSE), e.g., DSRC radio beacons, locates and charges tolls to the OBUs; and
“infrastructure-less” systems such as GNSS (global navigation satellite systems) toll systems, in which the OBUs autonomously locate themselves and transmit either “raw” position data (as so-called “thin clients”), or “finished” toll information calculated from the position data and toll maps (as so-called “thick clients”) to the toll center via a mobile-radio network (cellular network, CN).
Infrastructure-bound toll systems achieve a high degree of toll-charging security, but require extensive roadside infrastructure for this, in order to be able to locate OBUs over a large area, because the positional resolution of the location-finding is given from the size of the transmitting/receiving ranges and the number of beacons. Infrastructure-less toll systems, on the other hand, have basically unlimited coverage due to the self-locating-finding ability of the OBUs, but require enormous computational power (server farm) in the toll center for “thin client” systems in order to generate toll information from the raw position data of the OBUs, or in the case of “thick client systems,” require correspondingly expensive OBUs which can record and process all the toll maps of the toll coverage area, and this also presumes a correspondingly expensive distribution and updating of the toll maps via the mobile-radio network. This data traffic consumes bandwidth and, not least important, is expensive for the user.